Coin validators

ABSTRACT

A coin validator has a sensing arrangement disposed after an accept gate for detecting when a valid coin has moved past, and thus causing the triggering of the accumulation of credit. The sensing arrangement comprises a flap which is moved away from its normal position by the coin. If the coin is suspended on a string, the flap cannot move back to its normal position and therefore no credit is accumulated.

FIELD OF THE INVENTION BACKGROUND OF THE INVENTION

This invention relates to coin validators.

A well-known method of fraud associated with coin-operated machinesinvolves attaching string or thread to a genuine coin and then insertingthe coin into the machine while holding the string. Once the coin haspassed the validating section and caused an appropriate amount of creditto be accumulated, the user is able to stop the coin from passing into astorage section by use of the string. He can then operate the machine toobtain goods or services, and then retrieve the coin, for example bypressing an escrow return button.

Although there are a number of known techniques for avoiding thiscoin-on-a-string fraud, it would be desirable to provide a solutionwhich is very inexpensive to implement.

SUMMARY OF THE INVENTION

According to the present invention there is provided a coin validatorhaving a sensing arrangement which is arranged to detect the passage ofa coin which has left a testing section so as to trigger theaccumulation of credit, characterised in that the sensing arrangementcomprises a flap which is moved away from a first position by a coinleaving the testing section, and which will be held away from the firstposition by a thread attached to the coin and held by a user, thereby toinhibit the triggering of accumulation of credit.

It is known in validators to trigger the accumulation of credit onlyafter the coin has moved past a sensor. By the simple provision of theflap, this sensing arrangement can be able to detect the passage of thecoin by sensing when the flap returns to its first position. If it isprevented from returning by a thread attached to the coin, no credit isaccumulated. It is therefore possible to avoid coin-on-a-string fraud bythe simple addition of a flap to a known form of sensing arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

Arrangements embodying the invention will now be described by way ofexample with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a coin mechanism including a validatoraccording to the present invention;

FIG. 2 is a perspective, exploded view of a sensing arrangement in thevalidator;

FIG. 3 is a vertical cross section through part of the sensingarrangement;

FIG. 4 is a perspective view of a flap of the sensing arrangement; and

FIG. 5 is a perspective view of part of a sensing arrangement of anotherembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a coin mechanism 2 has a validator 4 whichcomprises a hopper 6 into which coins can be inserted. The coins fall onto a ramp 8 and then roll down the ramp past a testing region indicatedby the shaded section 10. The coins then fall towards an accept gateshown schematically at 12. If the coins have been tested and found notto be genuine, the coins are diverted by the accept gate 12 into areject path 14, which delivers the coins to a refund tray 16.

If the coins are acceptable, a solenoid is energised to cause the acceptgate 12 to shift into a position in which it opens an accept path 18leading to an escrow bucket 20. Coins entering the accept path 18 movepast a sensing arrangement shown generally at 22. After the sensingarrangement 22 has detected that a coin has moved past, it triggers theaccumulation of credit, thus permitting a user to operate a machine (notshown) in which the validator is housed. After the machine has providedgoods or a service to the value of the accumulated credit, an escrowaccept gate 24 is opened to allow a coin or coins held thereby to fallinto a cash box 26. Before provision of the goods or services, the usercan alternatively press an escrow return button (not shown) to cause anescrow return gate 28 to open and so allow coins in the escrow bucket 20to travel to the refund tray 16.

Arrangements generally of this type are well known, although thephysical structure of such arrangements varies substantially.

If the user attaches thread or cotton to the coin, he can prevent thecoin from being delivered to the cash box 26 by holding the thread.Therefore, by operating the escrow return button after the services orgoods have been provided, he can cause the coin to be delivered to therefund tray 16. In some arrangements, the user may be able to withdrawthe coin past the sensing arrangement 22 and accept gate 12, and then upthe ramp 8 so as to pull the coin out of the mouth of the hopper 6.

Such methods of fraud involve first allowing the coin to move past thesensing arrangement 22 so as to cause triggering of credit. The presentinvention relates to a method of avoiding fraud by preventing thesensing arrangement from detecting that the coin has moved past when thecoin is held by thread.

Referring to FIGS. 2 to 4, the sensing arrangement 22 is generallysimilar to that disclosed in EP-A-0 017 428, the disclosure of which isincorporated herein by reference. An infra-red light emitting diode 30emits a beam of infra-red light which traverses the passageway beneaththe accept gate 12. A prism 32 is located behind the wall at theopposite side of the passageway, and is arranged so as to reflect thebeam first through 90° so that it moves in the direction of the width ofthe passageway, and then through a further 90° so that it againtraverses the passageway and travels towards a photosensor 34 positionedbeside the diode 30. The beam thus traverses the passageway at twopositions spaced apart in the direction of the width of the passageway.

In the present embodiment, there is provided a flap 36 which carriesthereon a further prism 38 mounted in the path of the beam from thediode 30. The prism 38 is substantially identical to the prism 32, andhas the same function of reflecting the infrared beam first in thedirection of the width of the passageway, and then back to the sensor34.

The flap 36 has two integrally-formed C-shaped support members 40 whichsnap-fit on to respective horizontal shafts 42 which are carried byrespective pairs of downwardly-depending arms 44. This enables bothready attachment and detachment of the flap 36, and pivoting of the flapabout the axes of the shafts 42.

The weight of the prism 38 is such as to pivot the flap 36 in aclockwise direction in the orientation shown in FIG. 3, so that the flap36 is maintained normally in a horizontal orientation disposed acrossthe width of the accept path, with its outer edge 46 engaging beneath aledge 48 on the opposite side of the path from the prism 38. Apertures50 in the flap 36 render the structure lighter, so, that the weightneeded to bias the flap 36 to its normal position is small, andconsequently the flap can be pivoted easily away from this position.

When a coin is directed into the accept path 18 by the accept gate 12,it pushes the flap 36 out of the way as it moves past the flap. The flap36 then moves back to its original position shown in FIG. 3 when thecoin has moved past. This is detected by the sensing arrangement 22because the pivoting of the flap 36 changes the angle of the reflectingsurfaces of the prism 38 so that the light reflected back across thepassageway is no longer incident on the sensor 34. It will be noted fromFIG. 3 that even a small angle α of pivoting caused by the movement ofthe coin causes a displacement of the reflected beam by 2α.

As soon as the flap moves back to its original position, the sensor 34detects the reflected infra-red beam, and this in turn triggers theaccumulation of credit in an amount corresponding to the denomination ofthe coin as determined by the testing sections of the validator.

If, however, the coin is held on a thread, the thread will prevent theflap 36 from moving back to the position shown in FIG. 3, so that nocredit is accumulated.

It is not possible to use the thread to pull the coin back up past theflap 36 so as to cause the flap to pivot back and trigger theaccumulation of credit. This is prevented firstly by the flap 36 itself,and secondly by the accept gate 12. Also, some arrangements have adirectional sensor between the accept gate 12 and the sensingarrangement 22 so that movement in the reverse direction can be sensedand used to prevent the accumulation of credit and/or generate an alarmsignal.

Pressing an escrow return or reject button often moves apart the wallsof the coin passageway so as to free any jams which may have occurred.It may be therefore that pressing the reject button will permitsufficient room to allow the coin to be pulled back past the flap 36 andgate 12. However, pressing the reject button also often resets thesystem so that credit cannot be accumulated until a further coin isinserted into the validator. Also, in order to accumulate credit it ispreferably necessary for the sensing arrangement 22 to produce anindication that a coin has moved past (as defined in this case by thetrailing edge of the signal from the sensing arrangement) within apredetermined time period of a specific event, e.g. within apredetermined time period of passing a sensor disposed in front of theaccept gate 12, or within a predetermined time from the leading edge ofthe signal from the sensing arrangement 22. In such an arrangement,there would be insufficient time for the user to let the coin move pastthe flap, and then press the reject button and withdraw the coin tocause the accumulation of credit.

As mentioned above, the presence of the thread is sufficient to hold theflap 36 open and thereby prevent credit being awarded. This may dependupon the thread being under tension as a result of the weight of thecoin. Alternatively, the thickness of the thread may be sufficient tohold open the flap by the necessary amount. If the device relies uponthe tension in the thread, in some arrangements it might be possiblethat the thread will not go taut until after the coin has passed thesensing arrangement. This will cause the output signal temporarily toswitch levels, which may be sufficient to cause credit to be awarded. Ifdesired, the circuitry could be arranged to prevent this by deductingthe awarded credit if the sensor arrangement is operated again veryquickly after credit has been awarded, or by awarding credit only if thesensing arrangement remains unoperated for a predetermined amount oftime after a coin has moved past.

The prism 32 is not required in the present embodiment, and can beomitted. However, it is preferably provided for those situations inwhich the flap 36 is not desired, and consequently not fitted (e.g. incircumstances in which there is insufficient room for the flap 36).

FIG. 5 shows an alternative arrangement which is similar to theembodiment of FIGS. 2 to 4 and in which like reference numbers refer tolike elements. The prism 38 is replaced by an integrally-formedwedge-shaped member 52. As the flap 36 is rotated, the member 52 movesinto the path of the light beam from the prism 32 to the sensor 34. Thearrangement operates in exactly the same way, but in this case a largeramount of movement of the flap 36 is required before the light beam isprevented from reaching the sensor 34.

An additional advantage of the present invention results from the factthat the presence of the string is detected at a position located afterthe testing section and the accept gate. By the time the coin reachesthis position, the location of the string in the direction transverse tothe width of the coin passage is easy to predict. It would be moredifficult to predict the position near the entry to the validator andtherefore the string detector would be less reliable.

In the above arrangements, as the coin moves past the sensingarrangement, the sensor is first prevented from and then allowed toreceive light. This arrangement can be reversed so that the sensornormally detects no light, but the passage of the coin causes the flapto move out of the light path or to reflect light to the sensor, and theaccumulation of credit occurs when the sensor again receives no light.

Although the above embodiments use the preferred arrangement-whereby thelight beam traverses the passageway in two spaced-apart locations, thisis not essential. There may be a single light beam crossing thepassageway at only one location. Alternatively, some other form ofsensor than optical may be used, e.g. an inductive sensor responsive topart of the flap coming into proximity or moving out of proximity as theflap is pivoted away from its normal position.

We claim:
 1. A coin validator having an accept gate and a sensingarrangement which is arranged to detect the passage of a coin which hasleft a testing section and passed the accept gate so as to trigger theaccumulation of credit, wherein the sensing arrangement comprises a flapdownstream of the accept gate which is moved away from a first positionby a coin moving past the sensing arrangement, and which would be heldaway from the first position by a thread attached to the coin and heldby a user, thereby to inhibit the triggering of accumulation of credit.2. A validator as claimed in claim 1, wherein the sensing arrangementcomprises an optical sensor, and the flap is arranged to move betweenfirst and second positions, in one of which it interrupts a path oflight to the sensor and in the other of which it allows the light toreach the sensor.
 3. A validator as claimed in claim 1, wherein thesensing arrangement comprises an optical sensor, and the flap includesmeans for reflecting light, the flap being moveable between first andsecond positions, in one of which the light is reflected to the sensor,and in the other of which the light is reflected away from the sensor.4. A validator as claimed in claim 1, wherein the flap is biased bygravity to a position in which it extends across the width of a coinpassageway.
 5. A validator as claimed in claim 1, wherein the flap ismounted for pivotal movement.
 6. A validator as claimed in claim 1,wherein the flap is detachably mounted.
 7. A validator as claimed inclaim 6, wherein the sensing arrangement would be capable in the absenceof the flap of detecting the passage of a coin.
 8. A validator asclaimed in claim 1, wherein the validator is arranged to award creditonly if the sensing arrangement indicates that a coin has moved pastwithin a predetermined period of that coin having been initially sensedby the sensing arrangement.
 9. A validator as claimed in claim 1,wherein the validator is arranged to award credit only if the sensingarrangement indicates that a coin has moved past within a predeterminedperiod of that coin having been sensed at a position in front of theaccept gate.
 10. A coin validator comprising:an optical sensor proximatea coin path, downstream of a testing station; and a flap extendingacross the coin path, the flap comprising means for reflecting light andhaving a first position obstructing the coin path and a second positionnot obstructing the coin path, such that in the first position light isreflected from the means for reflecting to the sensor and in the secondposition light is not reflected from the means for reflecting to thesensor, the flap being adapted to be moved from the first position tothe second position by a coin moving along the coin path and the flapfurther being adapted to return to the first position from the secondposition after the passage of the coin, the flap capable of beingprevented from returning to its first position by a thread attached tothe coin and held by a user, wherein credit is not accumulated if theflap does not return to its first position.
 11. A coin validatorcomprising:a coin path; a testing station; a sensor positioned withrespect to the testing station and the coin path such that an insertedcoin first passes the testing station and then passes the sensor as thecoin moves along the coin path; a flap extending across the coin path,the flap having a first position obstructing a coin path and a secondposition not obstructing the coin path, the flap being moved from thefirst to the second position by a coin moving along the coin path andthe flap normally returning to its first position after the passage ofthe coin, the flap being adapted to be prevented from returning to itsfirst position after the coin passes the flap, if a string is attachedto the coin and held by a user; wherein the sensor detects whether theflap has returned to its first position after being moved to its secondposition by a passing coin, triggering the accumulation of credit unlessthe flap has not returned to its first position.
 12. A coin validatorcomprising:a testing station; a flap arranged downstream of the testingstation and arranged to be moved away from a first position by a coinmoving therepast and which would normally return to its first positionthereafter; a sensing arrangement responsive to the flap returning toits first position for enabling the accumulation of credit; the flapbeing arranged to be held away from the first position by a threadattached to the coin and held by a user, thereby to inhibit theaccumulation of credit.
 13. A method of operating a coin validatorcomprising:testing the acceptability of a coin; allowing an acceptablecoin to pass an accept gate; sensing the presence of a string attachedto the coin and held by a user after the coin has passed the acceptgate; triggering the accumulation of credit if no string is sensed; andinhibiting the accumulation of credit if a string is sensed.
 14. Themethod of claim 13, further comprising:moving a flap which has a firstposition obstructing the coin path and a second position not obstructingthe coin path, from its first to its second position, by the passage ofthe coin.
 15. The method of claim 14, wherein a string attached to thecoin and held by a user prevents the flap from returning to its firstposition.
 16. The method of claim 15, wherein the presence of a stringis sensed by determining whether the flap returns to its first position.17. The method of claim 16, wherein the accumulation of credit isinhibited if the flap does not return to its first position.
 18. Themethod of claim 17, further comprising inhibiting the accumulation ofcredit if the flap does not return to its first position within apredetermined period of time.